Computer-aided design (CAD) software allows a user to construct and manipulate complex three-dimensional (3D) models. A number of different modeling techniques can be used to create a 3D model. One such technique is a solid modeling technique, which provides for topological 3D models where the topological entities have corresponding supporting geometrical entities.
A design engineer designs physical and aesthetic aspects of 3D models, and is skilled in 3D modeling techniques. The design engineer creates parts and may assemble the parts into a subassembly or an assembly. A subassembly may also consist of other subassemblies. An assembly is designed using parts and subassemblies. Parts and subassemblies are hereinafter collectively referred to as components.
During the design process and once a 3D model is constructed, an engineer may simulate the design of a model to analyze and evaluate the real-world performance of the product being designed. Such a simulation may be executed by an engineering simulation application. An example of such an application is SOLIDWORKS® Simulation available from Dassault Systemes SolidWorks Corporation of Waltham, Mass., which uses the CAD model data to set up and execute simulation studies. Simulation may include finite element analysis (FEA) techniques. FEA can help determine strains and stresses under internal and external loads with respect to a 3D design of a product for manufacture.
FEA processes sub-divide a 3D model into distinctive elements, thereby creating a mesh with the goal of reducing the difficulty of a problem. Generally understood is that the more a mesh is refined, the more accurate are the results. This is the basic concept of “adaptive meshing” technology, which is a well-known, automatic approach in FEA to refine a mesh in a high stress area.
Stress singularity, however, is a common difficulty in such convergence practice. Stress singularity occurs when numerical errors increase with smaller mesh elements. In other words, no matter how the mesh is refined, the stress does not converge to the true solution. On the contrary, the stress diverges. Although this artificial high stress caused by the mathematical approach is well-known among simulation FEA analysts (many who earned a Ph.D. in Mechanical Engineering or related fields), CAD system users with less knowledge of FEA are often puzzled with regard to which result is accurate and whether the simulation result may be trusted. CAD system vendors may need to employ technical support personnel with an advanced education and knowledge in FEA to respond to customer queries. Moreover, often after receiving a response, a user may ask how to eliminate stress singularity to help validate a design.
The present invention assists a user who is not an expert in FEA by providing a tool to identify stress singularity and other common FEA difficulties (e.g., such as material, mesh, and stress concentration). Moreover, the present invention provides guidance to the user in overcoming these difficulties. Time-saving advantages and enhancements to current CAD systems are achieved by providing more efficient means for identifying and dealing with stress singularity.